Halogen-containing resin composition containing ester plasticizer

ABSTRACT

A plasticizer for halogen-containing resins which is composed of at least one compound expressed by the general formula ##STR1## wherein R 1  represents an aromatic hydrocarbon group containing 1 or 2 aromatic rings or an alicyclic hydrocarbon group having 4 to 37 carbon atoms, R 2   1 , R 2   2 , R 2   3  and R 2   4  are identical or different and each represents an aliphatic hydrocarbon group having 2 to 17 carbon atoms, R 3   1 , R 3   2 , R 3   3  and R 3   4  are identical or different and each represents an aliphatic hydrocarbon group having 2 to 22 carbon atoms, an aromatic hydrocarbon group or a heterocyclic group, each of n 1 , n 2 , n 3  and n 4  is 0 or an integer of 1 to 20 and the sum of these is 1 to 20, and each of m 1 , m 2 , m 3  and m 4  is 0 or 1 and the sum of these is 1 to 4. The plastizer has superior thermal stability, processability and compatibility. Halogen-containing resins plasticized with this plasticizer have especially high utility in applications requiring thermal stability.

This is a division, of application Ser. No. 175,764, filed Aug. 6, 1980,now U.S. Pat. No. 4,317,760 issued on Mar. 3, 1982.

This invention relates to a plasticizer for halogen-containing resinswhich has superior thermal stability, processability and compatibility,and to a resin composition comprising a halogen-containing resin and theplasticizer.

Plasticized vinyl chloride resin products have found extensiveapplications. In recent years, these resin products have been requiredto have higher heat-aging resistance as more rigorous safety regulationshave been set down on coated cables and automotive parts.

The heat-aging resistance of plasticized vinyl chloride resins isaffected by the types and amounts of stabilizers and plasticizers and ifpresent, fillers. Essentially, the effect of plasticizers is thegreatest. The heat-aging resistance of a plasticizer has to do with itsvolatility and heat decomposability, and generally, plasticizers havinghigher molecular weights have better heat-aging resistance because theyhave lower vapor pressures.

Known plasticizers having better heat-aging reistance thandi-2-ethylhexyl phthalate (DOP), a typical conventional plasticizer,include dialkyl esters of phthalic acid with monohydric alcohols having9 to 13 carbon atoms such as dinonyl phthalate, diisodecyl phthalate andditridecyl phthalate, and alkyl esters of aromatic tri- ortetra-carboxylic acids with monohydric alcohols having 6 to 10 carbonatoms such as trihexyl trimellitate, tri-2-ethylhexyl trimellitate(TOTM), triisodecyl trimellitate, and tetra-2-ethylhexyl pyromellitate.

Since, however, these plasticizers have a low ratio of polar groups inthe molecules because of the large number of carbon atoms of thealcohol, they have poor compatibility with vinyl chloride resins andpoor processability (e.g., insufficient gelling property), or have thedefect of bleeding on the surface of the resin.

Other known plasticizers include polyesters having a molecular weight of600 to 1000 composed of repetition of units of a dibasic carboxylic acidsuch as adipic acid and units of a glycol such as propylene glycol or1,3-butanediol, or a modification product thereof resulting frommodification of its ends with a fatty acid or an alcohol. Theseplasticizers have better heat-aging resistance when they have highermolecular weights, but on the other hand, have poor processability. Inaddition, when these polyesters are used in combination with lead-typestabilizers added mainly to cable-coating vinyl chloride resins, theycannot give sufficient electric insulation to the resins and moreoverhave very poor bleeding resistance at high humidity.

It is an object of this invention therefore to provide ahalogen-containing resin composition having especially high heat-agingresistance by discovering a plasticizer for halogen-containing resinswhich has superior compatibility, processability and bleeding resistanceas well as excellent heat-aging resistance.

It has now been found that the above object of this invention can beachieved by using as a plasticizer at least one compound of the generalformula ##STR2## wherein R₁ represents an aromatic hydrocarbon groupcontaining 1 or 2 aromatic rings or an alicyclic hydrocarbon grouphaving 4 to 37 carbon atoms, R₂ ¹, R₂ ², R₂ ³ and R₂ ⁴ are identical ordifferent and each represents an aliphatic hydrocarbon group having 2 to17 carbon atoms, R₃ ¹, R₃ ², R₃ ³ and R₃ ⁴ are identical or differentand each represents an aliphatic hdydrocarbon group having 2 to 22carbon atoms, an aromatic hydrocarbon group or a heterocyclic group,each of n₁, n₂, n₃ and n₄ is 0 or an integer of 1 to 20 and the sum ofthese is 1 to 20, and each of m₁, m₂, m₃ and m₄ is 0 or 1 and the sum ofthese is 1 to 4.

Thus, according to this invention, there is provided ahalogen-containing resin composition comprising (1) a halogen-containingresin and (2) a plasticizer composed of at least one compound of theabove general formula.

In the above general formula, R₁ is an aromatic carboxylic acid residuehaving 1 to 4 carboxyl groups and 1 or 2 aromatic rings or an alicycliccarboxylic acid residue having 1 to 4 carboxyl groups and 4 to 37 carbonatoms. Examples of the aromatic carboxylic acid are monocarboxylic acidssuch as benzoic acid and toluic acid, dicarboxylic acids such asphthalic acid, isophthalic acid, terephthalic acid, methylphthalic acid,naphthalenedicarboxylic acid, tetrachlorophthalic acid andtetrabromophthalic acid, tricarboxylic acids such as trimellitic acidand trimesic acid, tetracarboxylic acids such as pyromellitic acid andbenzophenonetetracarboxylic acid, and the anhydrides and esters of thesemono- to tetra-carboxylic acids. Examples of the alicyclic carboxylicacid include monocarboxylic acids such as cyclohexenecarboxylic acid andmethylcyclohexenecarboxylic acid, dicarboxylic acids such as Nadic acid,Het acid, tetrahydrophthalic acid, hexahydrophthalic acid,3-methyltetrahydrophthalic acid and 3-methylhexahydrophthalic acid,tricarboxylic acids such as 1,3-dimethyl-1,2,3-cyclohexanetricarboxylicacid and 1-carboxy-4-methylcyclohexyl-succinic acid, tetracarboxylicacids such as methylcyclohexenetetracarboxylic acid, and the anhydridesand esters of these mono- to tetra-carboxylic acids. In view of economyand the availability of raw materials, phthalic anhydride, isophthalicacid, terephthalic acid and trimellitic anhydride are preferred.

In the general formula, R₂ ¹, R₂ ², R₂ ³ and R₂ ⁴ are preferably adivalent aliphatic hydrocarbon group corresponding to X in a lactone ofthe general formula ##STR3## wherein X represents an aliphatichydrocarbon group having 2 to 17 carbon atoms, or a hydroxycarboxylicacid of the general formula ##STR4## wherein X is as defined above. Theymay be identical or different. Examples of the aforesaid lactone arebeta-propiolactone, gamma-butyrolactone, delta-valerolactone,epsilon-caprolactone, methyl-epsilon-caprolactone,dimethyl-epsilon-caprolactone, and trimethyl-epsilon-caprolactone.Lactic acid and ricinoleic acid are cited as examples of thehydroxycarboxylic acid. Of these, epsilon-caprolactone andmethyl-epsilon-caprolactone are preferred in view of economy and theease of the reaction operation.

As a component of (R₂ ¹ COO)_(n).sbsb.1, (R₂ ² COO)_(n).sbsb.2, (R₂ ³COO)_(n).sbsb.3, and (R₂ ⁴ COO)_(n).sbsb.4 in the above general formula,a polymer of the aforesaid lactone or hydroxycarboxylic acid may beused. This polymer is usually expressed by the general formula ##STR5##wherein Z is H or an alkyl group, n is an integer of 2 to 30, and X isas defined above. This polymer becomes the constituent component as aresult of molecular cleavage during synthesis of the plasticizer toreduce the number of repeating units to 20 or less. In the case of thelactone polymer, water or a monohydric alcohol having 1 to 22 carbonatoms in the alkyl group is used as an initiator. A specific example isa ring-opened polymer of a lactone such as epsilon-caprolactone ormethyl-epsilon-caprolactone obtained with water or a monohydric alcohol.

R₃ ¹, R₃ ², R₃ ³ and R₃ ⁴ preferably correspond to Y in a monohydricalcohol of the general formula Y--OH in which Y represents a hydrocarbongroup having 2 to 22 carbon atoms, preferably 6 to 18 carbon atoms. Theymay be identical or different. Examples of the monohydric alcoholinclude aliphatic monohydric alcohols such as butanol, hexanol,isohexanol, heptanol, isopheptanol, octanol, iso-octanol,2-ethylhexanol, decanol, isodecanol, undecanol, iso-undecanol, laurylalcohol, tridecanol, isotridecanol, tetradecanol, pentadecanol andhexadecanol, aromatic monohydric alcohols such as benzyl alcohol, andheterocyclic monohydric alcohols such as tetrahydrofurfuryl alcohol.

The plasticizer of this invention can be prepared by reacting compoundsconstituting the aforesaid R₁, R₂ and R₃ components in the absence orpresence of a solvent capable of forming an azeotrope with water, suchas toluene or xylene, at a temperature sufficient to distill out water.Alternatively, it may be prepared by reacting any two compounds forforming the R₁, R₂ and R₃ compounds and then reacting the remainingcompound with the reaction product to perform esterification orester-interchange reaction.

In the general formula, each of n₁, n₂, n₃ and n₄ is 0 or an integer of1 to 20, preferably 1 to 10, and the sum of these is 1 to 20, preferably1 to 10. If the sum of them exceeds 20, the resulting plasticizer hasdeteriorated electric insulation, processability and bleed resistancealthough its migration resistance and oil resistance are improved as themolecular weight increases. Accordingly, it is preferred to use not morethan 20 moles of a compound for forming the R₂ component per mole of acompound for forming the R₁ component. When the lactone polymer is usedas a compound for forming the R₂ compound, the average molecular weightof the polymer must be taken as 1 mole in calculation. In order topromote the reaction, it is desirable to use the compound for formingthe R₃ compound in an amount of at least 1 equivalent per carboxyl groupequivalent of the compound for forming the R₁ component.

In the synthesis of the plasticizer of this invention, it is preferredto use an esterification or ester-interchange reaction catalyst, forexample an acid catalyst such as sulfuric acid, p-toluenesulfonic acidor phosphoric acid or a metal compound catalyst such as zinc chloride,zinc acetate, lead oxide, tetraisopropyl titanate or dibutyltin oxidebecause such a catalyst serves to accelerate the reaction. In order torender the final product light in color, it is suitable to introduce aninert gaseous stream such as nitrogen gas.

Halogen-containing resins into which the plasticizer of this inventionis incorporated include polyvinyl chloride, polyvinylidene chloride,chlorinated polyolefins, a vinyl chloride/vinyl acetate copolymer, and avinyl chloride/vinylidene chloride copolymer. Chlorine-containing resinsare especially suitable.

The amount of the plasticizer in the halogen-containing resincomposition in this invention is usually about 5 to about 200 parts byweight, preferably 20 to 100 parts by weight, per 100 parts by weight ofthe halogen-containing resin. If desired, the plasticizer of thisinvention may be used in combination with known plasticizers used in thefield of processing polyvinyl chloride resins, for example phthalatessuch as DOP, adipates such as di-2-ethylhexyl adipate, trimellitatessuch as TOTM, epoxidized fatty acid esters, chlorinated fatty acidesters, chlorinated paraffins, phosphates, and polyesters derived fromadipic acid. The plasticizer of this invention may also be used togetherwith other additives such as stabilizers, fillers and pigments.

The halogen-containing resin composition in accordance with thisinvention is used in various applications. Specific applications includeautomotive applications as interior devices such as leathers, dashboardsand steering wheels, exterior devices such as side bumper, and windowpackings; electrical applications as cable sheaths, insulation tapes andtubes; and household good applications as hoses of electric washers,shower curtains, hoses of dryers, gaskets in refrigerators. It isespecially suitably used in applications which require heat-agingresistance.

The following Synthesis Examples and Example illustrate the presentinvention in greater details. It should be noted that the invention isin no way limited by these examples. All parts in these examples are byweight.

Synthesis Example 1

A reactor equipped with a reflux condenser was charged with 296 parts (2moles) of phthalic anhydride, 456 parts (4 moles) ofepsilon-caprolactone, 572 parts (4.4 moles) of 2-ethylhexanol, 124 partsof toluene and 6.2 parts of p-toluenesulfonic acid as a catalyst. In astream of nitrogen gas, they were heated with stirring, and toluene wasrefluxed at a maximum temperature of 140° C. While removing theresulting water continuously by a water separator, the reaction wascarried out for 7 hours until the acid value of the reaction mixturereached 3 or below. The crude ester was neutralized with sodiumcarbonate, washed with water, and steam-distilled at 120° to 130° C. toremove toluene and the excess (about 0.4 mole) of 2-ethylhexanol. Theresidue was dehydrated under reduced pressure, and cooled to 100° C.Activated carbon (6 parts) was added, and the mixture was stirred for 1hour and then filtered. There was obtained a plasticizer having aviscosity (measured at 25° C.) by the Gardner-Holdt method) of G, acolor (determined by the Gardner-Hellige method) of less than 1, an acidvalue of 0.17, an ester value of 359 and a volume inherent resistivity(30° C.) of 7.3×10¹¹ ohms-cm.

The molecular weight distribution of the resulting plasticizer wasmeasured by gel-permeation chromatography by comparison with a compoundof a known molecular weight such as DOP. It was found consequently thatthis plasticizer contained about 81% of a mixture of compounds of thefollowing structural formula (the main component of which consisted ofcompounds of the formula in which the sum of n₁ and n₂ is nearly equalto 2) and about 19% of DOP. ##STR6## (wherein Z₁ is a residue of2-ethylhexanol; n₁ +n₂ =1-20; n₁ and n₂ =0 or 1-20)

Synthesis Example 2

A reactor equipped with a reflux condenser was charged with 296 parts (2moles) of phthalic anhydride, 912 parts (8 moles) ofepsilon-caprolactone, 676 parts (5.2 moles) of 2-ethylhexanol and 8.5parts of p-toluenesulfonic acid as a catalyst. In a stream of nitrogengas, they were heated with stirring, and while continuously removing theresulting water, the reaction was performed at 140° C. for 6 hours untilthe acid value of the reaction mixture reached 3 or less. The crudeester was neutralized with sodium carbonate, washed with water, anddehydrated at 100° C. under reduced pressure. Then, the excess (about1.2 moles) of 2-ethylhexanol was removed at a maximum temperature of180° C. under a pressure of 2 torr. The residue was cooled to 100° C.,and 8.5 parts of activated carbon was added. The mixture was stirred for1 hour, and then filtered to afford a platicizer having a viscosity ofM-N, a color of less than 1, an acid value of 0.26, an ester value of396 and a volume inherent resistivity of 6.3×10¹¹ ohms-cm.

The molecular weight distribution of the plasticizer was measured in thesame way as in Synthesis Example 1. It was found that the resultingplasticizer contained about 89% of a mixture of compounds of the samestructural formula as given in Example 1 (the main component of whichconsisted of compounds of the formula in which n₁ +n₂ is nearly equal to4), about 9% of DOP and about 2% of compounds of the same structuralformula as in Example 1 in which n₁ plus n₂ exceeds 20.

Synthesis Example 3

A reactor was charged with 456 parts (4 moles) of epsilon-caprolactone,288 parts (2 moles) of a C₉ monoalcohol mixture (Diadol 9, a tradenamefor a product of Mitsubishi Chemical Co., Ltd.; composed of 50% oflinear C₉ alcohol and 50% of branched C₉ alcohol) and 0.39 part ofdibutyltin oxide as a catalyst. In a stream of nitrogen gas, they wereheated with stirring, and maintained at 200° C. for 3 hours to afford anaddition product of 2 moles on an average of the lactone with 1 mole of"Diadol 9." Then, 296 parts (2 moles) of phthalic anhydride was added,and the mixture was maintained at 200° C. for 3 hours to obtain a halfphthalate of the aforesaid adduct. Then, 461 parts (3.2 moles) of"Diadol 9" was added. A reflux condenser was attached to the reactor,and while continuously removing the resulting water by a waterseparator, the mixture was heated for 4 hours at a maximum temperatureof 220° C. until the acid value of the reaction mixture reached 2 orless. The excess (about 172.8 parts; about 1.2 moles) of "Diadol 9" wasremoved at a temperature of 190° C. and a pressure of 2 torr. Theresidue was cooled, and filtered to afford a plasticizer having aviscosity of D-E, a color of 1-2, an acid value of 0.18, an ester valueof 341 and a volume inherent resistivity of 4.0×10¹¹ ohms-cm.

The molecular weight distribution of the resulting plasticizer wasmeasured in the same way as in Synthesis Example 1. It was found thatthis plasticizer contained about 77% of a mixture of compounds of thefollowing structural formula (the main component of which consisted ofcompounds of the formula in which n₁ +n₂ =2), about 22% of the phthalateof "Diadol 9", and about 1% of compounds of the following structuralformula in which the sum of n₁ and n₂ exceeds 20. ##STR7## (wherein Z₂is a residue of C₉ monoalcohols; n₁ +n₂ is 1-20, and n₁ and n₂ are 0 or1-20)

Synthesis Example 4

A reactor was charged with 456 parts (4 moles) of epsilon-caprolactone,681 parts (5.2 moles) of a mixture of C₇, C₉ and C₁₁ monoalcohols(Diadol 711L, a tradename for a product of Mitsubishi Chemical Co.,Ltd.; average carbon number 8.1; containing 50% of linear alcohols and50% branched alcohols) and 0.37 part of tetraisopropyl titanate as acatalyst. In a stream of nitrogen gas, they were heated with stirring,and maintained at 200° C. for 3 hours to form a mixture of a lactoneadduct of "Diadol 711L" and unreacted "Diadol 711L". Then, 332 parts (2moles) of isophthalic acid was added. A reflux condenser was attached tothe reactor, and while continuously removing the resulting water by awater separator, the heating was continued at a maximum temperature of220° C. until the acid value of the reaction mixture reached 2 or less.The excess (150 parts) of the "Diadol 711L" was removed at 190° C. and 2torr. The residue was cooled to 100° C., and 6.2 g of hydroxide aluminummagnesium co-dried gel was added. The mixture was stirred for 1 hour,and then filtered to afford a plasticizer having a viscosity of E-F, acolor of 1-2, an acid value of 0.11, an ester value of 358 and a volumeinherent resistivity of 6.8×10¹¹ ohms-cm.

The molecular weight distribution of the resulting plasticizer wasmeasured in the same way as in Synthesis Example 1. It was found thatthis plasticizer contained about 80% of a mixture of compounds of thefollowing structural formula (the main component of which consisted ofcompounds of the formula in which n₁ +n₂ is nearly equal to 2) and about20% of the isophthalate of "Diadol 711L". ##STR8## (wherein Z₃represents residues of C₇, C₉ and C₁₁ monoalcohols; the sum of n₁ and n₂is 1 to 20; n₁ and n₂ represent 0 or 1 to 20)

Synthesis Example 5

A reactor was charged with 948 parts (2 moles) of diundecyl phthalatederived from phthalic anhydride and a C₁₁ monoalcohol mixture (Diadol11, a tradename for a product of Mitsubishi Chemical Co., Ltd.; composedof 50% of linear C₁₁ alcohol and 50% of branched C₁₁ alcohol), 508 parts(4 moles as lactone units) of poly(epsilon-caprolactone) having anaverage molecular weight of 1000 and prepared by using n-hexanol as aninitiator, and 0.4 part of dibutyltin oxide as a catalyst. In a streamof nitrogen gas, they were heated with stirring, and maintained at 210°C. for 20 hours to perform the reaction until the ester-interchangereaction reached equilibrium. Then, the reaction mixture was treated atthe same temperature under a pressure of 2 torr to remove 50 g of afraction composed mainly of n-hexanol. The residue was cooled to 100°C., and filtered to afford a plasticizer having a viscosity of F, acolor of 3, an acid value of 0.20, an ester value of 311, a hydroxylvalue of 1.2 and a volume inherent viscosity of 3.7×10¹¹ ohms-cm.

The molecular weight distribution of the resulting plasticizer wasmeasured in the same way as in Synthesis Example 1. It was found thatthis plasticizer contained about 76% of a mixture of compounds of thefollowing structural formula (the main component of which consisted ofcompounds of the formula in which the sum of n₁ and n₂ is nearly equalto 2), about 22% by weight of the unreacted diundecyl phthalate andabout 2% by weight of compounds of the following formula in which thesum of n₁ and n₂ exceeds 20. ##STR9## (wherein Z₄ represents a residueof C₁₁ monoalcohol; the sum of n₁ and n₂ is 1 to 20; n₁ and n₂ are 0 or1 to 20)

Synthesis Example 6

A reactor equipped with a reflux condenser was charged with 192 parts (1mole) of trimellitic anhydride, 114 parts (1 mole) ofepsilon-caprolactone, 507 parts (3.9 moles) of 2-ethylhexanol and 0.2part of tetraisopropyl titanate as a catalyst. In a stream of nitrogengas, they were heated with stirring, and while continuously removing theresulting water by a water separator, the heating was continued for 6hours at a maximum temperature of 220° C. until the acid value of thereaction mixture reached 2 or less. The excess (about 0.9 mole) of2-ethyl hexanol was removed at 180° C. and 2 torr. The residue wascooled to 100° C., and then filtered to afford a platicizer having aviscosity of H-I², a color of 3-4, an acid value of 0.13, an ester valueof 339 and a volume inherent resistivity of 8.8×10¹¹ ohms-cm.

The molecular weight distribution of the resulting plasticizer wasmeasured in the same way as in Synthesis Example 1. It was found thatthis plasticizer contained about 65% of a mixture of compounds of thefollowing structural formula (the main component of which consisted ofcompounds of the formula in which the sum of n₁, n₂, and n₃ is nearlyequal to 1) and about 35% of TOTM. ##STR10## (wherein Z₅ is a residue of2-ethylhexanol; the sum of n₁, n₂ and n₃ is 1 to 20; n₁, n₂ and n₃ are 0or 1 to 20)

Synthesis Example 7

A reactor equipped with a reflux condenser was charged with 192 parts (1mole) of trimellitic anhydride, 342 parts (3 moles) ofepsilon-caprolactone, 429 parts (3.3 moles) of 2-ethylhexanol and 4.4parts of p-toluenesulfonic acid as a catalyst. In a stream of nitrogengas, the heating was carried out. The mixture was maintained at amaximum temperature of 140° C., and while continuously removing theresulting water by a water separator, the reaction was carried out for11 hours until the acid value of the reaction mixture reached 3 or less.The reaction mixture was worked up in the same way as in SynthesisExample 1 to afford a plasticizer having a viscosity of N-O, a color of1, an acid value of 0.24, an ester value of 378 and a volume inherentresistivity of 1.2×10¹² ohms-cm.

The molecular weight distribution of the resulting plasticizer wasmeasured in the same way as in Synthesis Example 1. It was found thatthis plasticizer contained 96% of a mixture of compounds of the samestructural formula as given in Synthesis Example 6 (the main componentof which consisted of compounds of the formula in which the sum of n₁,n₂ and n₃ is nearly equal to 3) and about 4% of compounds of thestructural formula of Synthesis Example 6 in which the sum of n₁, n₂ andn₃ exceeds 20.

Synthesis Example 8

A reactor equipped with a reflux condenser was charged with 192 parts (1mole) of trimellitic anhydride, 684 parts (6 moles) ofepsilon-caprolactone, 429 parts (3.3 moles) of 2-ethylhexanol, 123 partsof toluene and 6.1 parts of p-toluenesulfonic acid as a catalyst. In astream of nitrogen gas, the heating was carried out with stirring.Toluene was refluxed at a maximum temperature of 140° C. Whilecontinuously removing the resulting water by a water separator, thereaction was carried out for 6 hours until the acid value of thereaction mixture reached 3 or less. The reaction mixture was then workedup in the same way as in Synthesis Example 1 to afford a plasticizerhaving a viscosity of T-U², a color of less than 1, an acid value of0.20, an ester value of 407 and a volume inherent resistivity of1.9×10¹² ohms-cm.

The molecular weight distribution of the resulting plasticizer wasmeasured in the same way as in Synthesis Example 1. It was found thatthis plasticizer contained about 94% by weight of a mixture of compoundsof the same structural formula as given in Synthesis Example 6 (the maincomponent of which consisted of compounds of the formula in which thesum of n₁, n₂ and n₃ is nearly equal to 6) and about 6% of compounds ofthe same structural formula in which the sum of n₁, n₂ and n₃ exceeds20.

Synthesis Example 9

A reactor equipped with a reflux condenser was charged with 192 parts (1mole) of trimellitic anhydride, 1026 parts (9 moles) ofepsilon-caprolactone, 429 parts (3.3 moles) of 2-ethylhexanol, 157 partsof toluene and 7.9 parts of p-toluenesulfonic acid as a catalyst. In astream of nitrogen gas, they were heated with stirring, and at a maximumtemperature of 140° C., toluene was refluxed. While continuouslyremoving the resulting water by a water separator, the reaction wascarried out for 7 hours until the acid value of the reaction mixturereached 3 or less. The reaction mixture was then worked up in the sameway as in Synthesis Example 1 to afford a plasticizer having a viscosityof V-W³ (a white solid at 20° C. or below), a color of 1-2, an acidvalue of 0.25, an ester value of 429, and a volume inherent resistivityof 2.0×10¹² ohms-cm.

The molecular weight distribution of the resulting plasticizer wasmeasured in the same way as in Synthesis Example 1. It was found thatthis plasticizer contained about 90% of a mixture of compounds of thesame structural formula as given in Synthesis Example 6 (the maincomponent of which consisted of compounds of the formula in which thesum of n₁, n₂ and n₃ is nearly equal to 9) and about 10% of compounds ofthe same structural formula in which the sum of n₁, n₂ and n₃ exceeds20.

Synthesis Example 10

A reactor equipped with a reflux condenser was charged with 192 parts (1mole) of trimellitic anhydride, 342 parts (3 moles) ofepsilon-caprolactone, 475 parts (3.3 moles) of "Diadol 9", 93 parts oftoluene and 4.7 parts of p-toluenesulfonic acid. In a stream of nitrogengas, they were heated with stirring. While maintaining the mixture at amaximum temperature of 140° C., it was reacted for 6 hours until theacid value of the reaction mixture reached 3 or less. The reactionmixture was then worked up in the same way as in Synthesis Example 1 toafford a plasticizer having a viscosity of K² -L, a color of less than1, an acid value of 0.26, an ester value of 358 and a volume inherentresistivity of 9.0×10¹¹ ohms-cm.

The molecular weight distribution of the resulting plasticizer wasmeasured in the same way as in Synthesis Example 1. It was found thatthis plasticizer contained about 95% of a mixture of compounds of thefollowing structural formula (the main component of which consisted ofcompounds of the formula in which the sum of n₁, n₂ and n₃ is nearlyequal to 3) and about 5% of compounds of the following structuralformula in which the sum of n₁, n₂ and n₃ exceeds 20. ##STR11## (whereinZ₆ is a residue of C₉ monoalcohol; the sum of n₁, n₂ and n₃ is 1 to 20;n₁, n₂ and n₃ are 0 or 1 to 20)

Synthesis Example 11

A reactor equipped with a reflux condenser was charged with 192 parts (1mole) of trimellitic anhydride, 342 parts (3 moles) ofepsilon-caprolactone, 568 parts (3.3 moles) of "Diadol 11", 101 parts oftoluene and 5.1 parts of p-toluenesulfonic acid as a catalyst. In astream of nitrogen-gas, they were heated with stirring, and at a maximumtemperature of 140° C., toluene was refluxed. While continuouslyremoving the resulting water by a water separator, the reaction wascarried out for 7 hours until the acid value of the reaction mixturereached 3 or less. The reaction mixture was worked up in the same way asin Synthesis Example 1 to afford a plasticizer having a viscosity ofK-L, a color of less than 1, an acid value of 0.19, an ester value of329 and a volume inherent resistivity of 1.1×10¹² ohms-cm.

The molecular weight distribution of the resulting plasticizer wasmeasured in the same way as in Synthesis Example 1. It was found thatthis plasticizer contained about 96% of a mixture of compounds of thefollowing structural formula (the main component of which consisted ofcompounds of the formula in which the sum of n₁, n₂ and n₃ is nearlyequal to 3) and about 4% of compounds of the following formula in whichthe sum of n₁, n₂ and n₃ exceeds 20. ##STR12## (wherein Z₇ represents aresidue of C₁₁ monoalcohol; the sum of n₁, n₂ and n₃ is 1 to 20; n₁, n₂and n₃ are 0 or 1 to 20)

Example

A sheet was prepared in accordance with the following basic compoundingrecipe and molding conditions using each of the plasticizers obtained inSynthesis Examples 1 to 11 and DOP as a prior art plasticizer(containing dissolved therein 0.5% of bisphenol A as an antioxidant).

    ______________________________________                                        Basic compounding recipe                                                      Polyvinyl chloride (DP = 1450)                                                                        100    parts                                          Plasticizer             50     parts                                          Tribasic lead sulfate   5      parts                                          Lead stearate           1      part                                           Molding conditions                                                            Roll (6 inches in diameter): 165° C. × 10 minutes                Press (1 mm thick): 170° C. × 5 minutes                          ______________________________________                                    

The resulting sheets were tested for the following properties, and theresults are tabulated below.

(1) Hardness (JIS spring A scale)

Measured substantially in accordance with JIS-K6301.

(2) Tensile Test

Measured substantially in accordance with JIS-K6723.

(3) Heat Aging Test

Performed substantially in accordance with JIS-K6723. The test wasconducted at 136° C. for 168 hours, and at 158° C. for 168 hours,respectively. The results are shown by percent weight loss (%) andpercent residual elongation (%) after the test. The sign "-" in thecolumn of the percent residual elongation shows that the measurement wasimpossible because the specimen was hardened.

(4) Test for bleeding at high humidity

A roll sheet having a thickness of 0.3 mm was prepared from the abovebasic compound, and a test specimen, 40 mm×100 mm in size, was cut off.The test specimen was allowed to stand in a vessel kept at 70° C. and arelative humidity of 98%. The degree of bleeding of the test specimenwas determined 5 days later. The circle mark in the following tableshows that no bleeding phenomenon was noted.

(5) Low temperature flexibility test

Measured substantially in accordance with ASTM D-1043-51.

(6) Brabender gelling speed

Fifty grams of the above basic compound was taken, and pre-dried at 50°C. for 1 hour. The dried sample was filled in a Brabender plasticorder.Its rotation at 60 r.p.m. was started at a jacket temperature of 165°C., and the time (seconds) which elapsed until a maximum torque wasreached was determined.

    __________________________________________________________________________                                                  Test                                                                          for                                                       Heat aging test     bleed-                                                    136° × 168 hours                                                           158° C. × 168                                                              ing at                                                                            Low                                                        Percent   Percent                                                                            high                                                                              temper-                     Hardness   Tensile test   Percent                                                                            residual                                                                           Percent                                                                            residual                                                                           hu- ature                                                                              Brabender                    (JIS 100% Tensile                                                                            Elonga-                                                                            weight                                                                             elonga-                                                                            weight                                                                             elonga-                                                                            midity                                                                            flexi-                                                                             gelling                      spring                                                                             Modulus                                                                            strength                                                                           tion loss tion loss tion (5 days                                                                           bility                                                                             speed                  Plasticizer                                                                         A scale)                                                                           (kg/cm.sup.2)                                                                      (kg/cm.sup.2)                                                                      (%)  (%)  (%)  (%)  (%)  later)                                                                            (°C.)                                                                       (seconds)              __________________________________________________________________________    Synthesis                                                                           91   116  252  339  7.0  84   14.8 58   ○                                                                          -18  45                     Example 1                                                                     Synthesis                                                                           92   116  258  343  3.2  91   12.4 55   ○                                                                          -15  40                     Example 2                                                                     Synthesis                                                                           92   115  248  354  6.0  85   13.0 52   ○                                                                          -19  45                     Example 3                                                                     Synthesis                                                                           93   120  256  350  6.1  84   13.1 54   ○                                                                          -21  45                     Example 4                                                                     Synthesis                                                                           94   122  250  368  3.8  91   10.9 52   ○                                                                          -23  45                     Example 5                                                                     Synthesis                                                                           96   135  258  344  1.0  97    9.6 58   ○                                                                          -14  40                     Example 6                                                                     Synthesis                                                                           96   134  247  348  0.6  98    8.7 59   ○                                                                          -14  35                     Example 7                                                                     Synthesis                                                                           96   130  257  338  0.8  98   10.1 58   ○                                                                          -10  35                     Example 8                                                                     Synthesis                                                                           96   138  263  322  0.6  97   11.8 53   ○                                                                          -10  35                     Example 9                                                                     Synthesis                                                                           96   146  263  359  0.5  98    7.7 57   ○                                                                          -18  40                     Example 10                                                                    Synthesis                                                                           98   166  257  334  0.4  99    8.2 59   ○                                                                          -16  40                     Example 11                                                                    DOP   92   110  206  345  26.0 --   40.1 --   ○                                                                          -22  40                     __________________________________________________________________________

What we claim is:
 1. A halogen-containing resin composition comprising(1) a halogen-containing resin and (2) as a plasticizer, at least onecompound of the general formula ##STR13## wherein R₁ represents anaromatic hydrocarbon group containing 1 or 2 aromatic rings or analicyclic hydrocarbon group having 4 to 37 carbon atoms, R₂ ¹, R₂ ², R₂³ and R₂ ⁴ are identical or different and each represents an aliphatichydrocarbon group having 2 to 17 carbon atoms, R₃ ¹, R₃ ², R₃ ³ and R₃ ⁴are identical or different and each represents an aliphatic hydrocarbongroup having 5 to 22 carbon atoms, an aromatic hydrocarbon group or aheterocyclic group, each of n₁, n₂, n₃ and n₄ is 0 or an integer of 1 to20 and the sum of these is 1 to 20, and each of m₁, m₂, m₃ and m₄ is 0or 1 and the sum of these is 1 or
 2. 2. The composition of claim 1wherein said halogen-containing resin is a chlorine-containing resin. 3.The composition of claim 1 wherein said plasticizer is prepared byreacting (i) an aromatic dicarboxylic acid containing 1 or 2 aromaticrings or an alicyclic dicarboxylic acid having 4 to 37 carbon atoms,(ii) a lactone of the general formula ##STR14## wherein X represents analiphatic hydrocarbon group having 5 to 17 carbon atoms, ahydroxycarboxylic acid of the general formula ##STR15## wherein X is asdefined, or a polymer of any of these, and (iii) a monohydric alcohol ofthe general formula

    Y-OH

wherein Y represents a hydrocarbon group having 2 to 22 carbon atoms. 4.The composition of claim 1 comprising 100 parts by weight of thehalogen-containing resin and 5 to 200 parts by weight of theplasticizer.
 5. The composition of claim 3 wherein said reactant (i) isan aromatic dicarboxylic acid selected from the group consisting ofphthalic acid, isophthalic acid, terephthalic acid, methylphthalic acid,naphthalenedicarboxylic acid, tetrachlorophthalic acid andtetrabromophthalic acid or an anhydride or esterified product thereof.6. The composition of claim 3 wherein said reactant (ii) is a lactoneselected from the group consisting of ε-caprolactone,methyl-ε-caprolactone, dimethyl-ε-caprolactone andtrimethyl-ε-caprolactone.
 7. The composition of claim 3 wherein saidreactant (ii) is ricinoleic acid.
 8. The composition of claim 3 whereinthe monohydric alcohol (iii) is an aliphatic monovalent alcohol selectedfrom the group consisting of butanol, hexanol, isohexanol, heptanol,isoheptanol, octanol, isooctanol, 2-ethylhexanol, decanol, isodecanol,undecanol, isoundecanol, lauryl alcohol, tridecanol, isotridecanol,tetradecanol, pentadecanol and hexadecanol.
 9. The composition of claim3 wherein the monohydric alcohol (iii) is benzyl alcohol.
 10. Thecomposition of claim 3 wherein the monohydric alcohol (iii) istetrahydrofurfuryl alcohol.
 11. The composition of claim 1 wherein thesum of m₁, m₂, m₃ and m₄ is
 2. 12. The composition according to claim 2wherein said chlorine-containing resin is selected from the groupconsisting of polyvinyl chloride, polyvinylidene chloride, chlorinatedpolyolefin, vinyl chloride/vinyl acetate copolymer and vinylchloride/vinylidene chloride copolymer.
 13. The composition of claim 1comprising 100 parts by weight of the halogen-containing resin and 20 to100 parts by weight of the plasticizer.
 14. The composition of claim 1wherein the plasticizer is at least one compound of the formula##STR16## wherein Z₁ is a residue of 2-ethylhexanol, a residue of C₉monoalcohols or a residue of C₁₁ monoalcohols.
 15. The composition ofclaim 14 wherein Z₁ is 2-ethylhexyl and the sum of n₁ and n₂ is about 2.16. The composition of claim 1 wherein the plasticizer is at least onecompound of the formula ##STR17## wherein Z₃ represents residues of C₇,C₉ and C₁₁ monoalcohols.